Apparatus for dispensing compressed gas at programmed pressure and volume

ABSTRACT

Apparatus for filling containers such as gas cylinders with predetermined pressure and volume of a compressed gas. The disclosed embodiment of the present apparatus is useful for userpaid vending of refills for air tanks of the kind used for scuba diving apparatus, and provision is made for preprogrammed selection of the appropriate pressure and volume or air to be supplied to a particular air tank. The apparatus includes provision for temporary suspension of tank filling without disrupting the fill vending cycle, for bleeding air pressure from a tank connecting conduit upon completion of a filling operation, and also includes apparatus which prevents unauthorized or improper use of the dispensing apparatus.

1 United States Patent 1191 Douglass Mar. 26, 1974 Primary ExaminerHarvey C. Hornsby Assistant Examiner-Philip R. Coe Attorney, Agent, or Firm-Jones, Thomas & Askew [76] Inventor: Mayward Clyde Douglass, 2678 t1 t 3 4 Warwick Cir A an a Ga 03 5 ABSTRACT [22] Flled: 1972 Apparatus for filling containers such as gas cylinders [2]] Appl. No.: 238,242 with predetermined pressure and volume of a compressed gas. The disclosed embodiment of the present apparatus is useful for user-paid vending of refills for [52] 3 4 air tanks of the kind used for scuba diving apparatus, [5 I] c 2 5. 222 and provision is made for preprogrammed selection of [58] d 0 Search 1 l 3 5 the appropriate pressure and volume or air to be sup- 141/18 3 plied to a particular air tank. The apparatus includes provision for temporary suspension of tank filling [56] References and without disrupting the till vending cycle, for bleeding UNITED STATES PATENTS air pressure from a tank connecting conduit upon 2,695,122 11/1954 Learman 222/3 X completion of a filling operation, and also includes ap- 2,855,926 0/ K pp ma 19 /3 X paratus which prevents unauthorized or improper use Kennedy u. of the dispensing apparatus 3,191,801 6/l965 Standish 222/3 X 3,208,574 9/1965 Anson 194/3 1 l m 7 Dr wing Fig res open/nave wsrfluc'r/mvs l6 l0 Q'IIIC' READY DEPOSIT 4 50" 3 o v 1 m TANK 1s 77 PUSH HOLD Fl LLED Pll-JSl-ll3 B EE E I5 PATENTEI] R26 I974 SHEET 1 OF 3 FIG 2 DEPOSIT TANK IS FILLED I l I P I I l I I FIG FIG

FIG

PAIENTEDHARZ mm 3.799.218

SHEET 2 OF 3 FILLED APPARATUS FOR DISPENSING COMPRESSED GAS AT PROGRAMMED PRESSURE AND VOLUME This invention relates in general to dispensing apparatus and in particular to apparatus for dispensing compressed air or other gases to a container under desired parameters of pressure and/or volume.

The general popularity and availability of selfcontained underwater breathing apparatus, popularly known as scuba diving equipment, is well-known and needs little introduction, since various types of scuba apparatus enjoy widespread popularity with both sport and commercial divers. Scuba apparatus generally includes one or more air tanks which are carried by the diver and which supply pressurized air, or other gases including oxygen, to a regulator for supplying the air or other gas to the diver according to his breathing demands. Scuba tanks are provided in a number of volumes and maximum operating pressures, to provide divers with a variable number of available diving times before the tanks must be refilled.

Scuba tanks are generally filled by connecting the tank to an appropriate air compressor or other suitable source of compressed air, and this filling operation in the prior art typically requires the constant presence of an attendant to insure that the proper connections are made between the air tank and the source of air, that valves are opened and closed in the proper sequence, and additionally to make certain that only authorized, i.e., paying, use is made of the tank refilling apparatus. Moreover, the necessity for refilling of various sizes of scuba tanks which have different volumes and maximum fill pressures make additional demands for the constant presence of an attendant during the refilling operation.

Accordingly, it is an object of the present invention to provide improved apparatus for dispensing compressed gas.

It is another object of the present invention to provide improved apparatus for dispensing compressed gas at selected pressures and volumes.

It is still another object of the present invention to provide compressed gas dispensing apparatus which is usable without the required presence of a special attendant.

It is still another object of the present invention to provide compressed gas dispensing apparatus which vends a compressed gas at a predetermined pressure and maximum volume.

Other objects as well as many of the attendant advantages of the present invention will become more readily apparent from the following description of apparatus embodying the present invention, and in which:

FIG. 1 shows an elevation view of the control panel of apparatus according to a disclosed embodiment of the present invention;

FIG. 2 shows a plan view of a coded selector card according to the disclosed embodiment;

FIG. 3 shows a plan view of decoding apparatus according to the disclosed embodiment;

FIG. 4 is a section view taken along line 4-4 of FIG.

FIG. 5 is a schematic diagram showing a gas dispensing circuit according to the disclosed embodiment; and

FIGS. 6A and 6B show a schematic diagram showing the control circuitry of the disclosed embodiment.

Stated in general terms, the present invention provides gas dispensing apparatus in which the desired preprogrammed pressure and volume of gas to be dispensed is selected by a device such as a coded card which is inserted in the apparatus. The user of the apparatus is informed of the amount of money required to accomplish the desired preprogrammed vending of compressed gas, and upon insertion of the appropriate amount of money the vending flow of gas commences. Circuitry is provided which terminates the operation of a particular vending cycle after exploration of the period of time normally required to fill a tank of the selected predetermined volume, so that an unauthorized refill of another tank cannot be accomplished immediately following completion of an authorized tank fill.

Stated more particularly, and with reference taken to the disclosed embodiment of the present invention as shown in the Figures, there is shown generally at 10 an exemplary control panel of gas vending apparatus constructed according to the present invention and especially useful for refilling scuba air tanks. As shown in FIG. 1, the apparatus includes a control panel 11 from which extends a gas conduit or hose 12 terminating in a fitting l3 appropriate for interconnection with a scuba air tank. The panel 11 is provided with a slot 14 for receiving an appropriate selector card, as described below, and a coin slot 15 for accepting deposit of the amount of money required for a desired tank refilling operation. A placard 16 listing the simplified instructions for operating the vending apparatus is prominantly displayed on the panel 1 l. The remainder of the controls and illuminated signals on the panel 11 are described below with reference to the appropriate circuits and functioning of the apparatus.

In discussing the construction and operation of the described embodiment of the present invention, it is assumed that the apparatus will be used to vend air to scuba tanks having two possible maximum-fill pressures, such as 1800 psi and 2250 psi; and having two independently-selected volume capacities such as 72 cubic feet and 144 cubic feet. These two possible choices of two different variables provide a combination of four possible separate combinations of pressure and volume which may be represented by a particular scuba tank to be refilled, although it will be understood by those skilled in the art that the foregoing specific values of pressure and volume are stated by way of example only and that alternative and additional pressures and/or volumes may be provided as necessary or desirable.

The gas dispensing apparatus of the present invention is made ready to dispense compressed air, according to the disclosed embodiment, at a selected one of these possible pressures and volumes by inserting into the card slot I4 a coded selector card 20, shown in FIG. 2, having fill information and an antifraud provision encoded by the location of apertures in the cards. The aperture 21 in the depicted location, for example, corresponds to a scuba tank having a maximum capacity of 72 cubic feet at 2250 psi; the other apertures 22, 23, and 24, which are shown in phantom in FIG. 2, represent the locations of apertures which would alternatively be provided in the card 20 for the other three combinations of scuba tank pressure and volume, as mentioned above. The aperture 25 provides an antifraud function as described below. The card 20 may conveniently include indicia such as the arrow 26 containing the word INSERT to denote the proper orientation of the card for insertion into the card slot 14.

The presence or absence of apertures in a card 20 as inserted into the card slot 14 causes selective actuation of certain ones of the selector switches S2, S3, S4, S5, S6, and S7 which comprise a decoding mechanism 27 positioned behind the panel 11 to receive the card 20 and provide output signals corresponding to the information encoded in the card. Each of the selector switches 52-57, which may be magnetically controlled reed switches, is positioned in a plane disposed on one side of the card slot 14, as best shown in FIGS. 3 and 4. A corresponding series of permanent magnets 28, 29, 30, 31, 32, and 33 are positioned in a plane disposed on the other side of the card slot 14, also as best shown in FIGS. 3 and 4, so that each of the aforementioned magnets is disposed in operating relation with a corresponding one of the magnetically operated selector switches 82-87. It will be appreciated that each of these magnets operates on the corresponding selector switch to maintain that switch in a particular actuated state, in the absence of any magnetic shield disposed in the card slot 14 to isolate the selector swithces from the corresponding magnets.

To provide the desired function of selecting only certain ones of the selector switches S2S7, the selector card 20 may advantageously be made of a ferrous material such as a thin sheet of steel having appropriate apertures punched or otherwise formed therein and which may be completely encapsulated as by being sandwiched between two layers of an opaque plastic material or the like. Assuming that such a selector card 20 is provided having the apertures 21 and 25 disposed in the ferrous material thereof, insertion of this card into the slot 14 positions the aperture 21 between the selector switch S4 and the magnet 30, and also positions the aperture 25 between the selector switch S3 and the magnet 29. The positioning of the two apertures 21 and 25 thus maintains the magnetic field between the two magnets 29 and 30 and the respective selector switches S3 and S4, thereby maintaining these two selector switches in the actuated state. However, the presence of a ferrous layer between the remainder of the magnets 28, 31, 32, and 33 shields the corresponding magnetic fields from the respective selector switches S2, S5, S6 and S7, and so these four selector switches become switched to an unactuated state. A control switch S1 is positioned adjacent the closed end of the card slot 14 to be actuated by actual contact or otherwise with a selector card 20 fully inserted into the card slot.

Turning next to the schematic diagram as shown in FIG. 6, the structural and operational interrelation between the decoding apparatus 27 and the remainder of the gas dispensing apparatus is seen from the operating interconnection of the selector switches 84-57 with corresponding ones of individual function control relays RL1, RL2, RL3, and RL4. Each of the four function control relays has a plurality of sets of contacts designated A-F in the disclosed embodiment and each of these contacts as well as the contacts of the other relays and switches in this embodiment, with the exception of the RLl and as otherwise specified, is shown in a normally deenergized state. Each of the selector switches 82-57 is depicted in FIG. 6 to depict the operating state maintained when these switches are all subjected to their respective magnetic fields, that is, the states maintained by these selector switches in the absence of any selector card 20 in the card slot 14.

Considering control voltage extending from an appropriate power supply 38 through contact 39 of relay RL8 and the closed contact of pressure switch PS-3, extending along the line 40 and then to a line 41 connected in parallel with all of the relay armatures in contact set A, it can be seen that none of the function control relays RLl-RL4 can be actuated since the circuit through the relay coils to ground is broken by selector switch S2, magnetically maintained open, and also by the position of S1, shown in FIG. 6 in the position maintained when no selector card 20 is disposed in the card slot 14. It will be seen that the READY light 42 is illuminated at this time through a circuit extending from the line 40 and the switch S1 to ground.

Assume now that a scuba tank to be refilled is attached to the fitting 13, the air valve on the scuba tank is opened to permit filling, and a selector card 20 as shown in FIG. 2 is inserted into the card slot 14. The presence of the selector card moves the switch S] from the position shown in FIG. 6 to make contact with the switch terminal 43, thereby extinguishing the READY light 42 and applying an electrical ground to one side of the selector switch S2. Since the particular selector card 20 contains apertures 21 and 25 to maintain the magnetically operated states of the selector switches S3 and S4, it will be understood that the remaining selector switches S2 and -87 assume conductive positions the opposite of those depicted in FIG. 6. Thus, the selector switch S2 becomes conductive to establish an operating circuit including S3 and S4 (permitted to remain closed by the apertures 25 and 21) and function control relay RLl, thereby energizing that relay to place the respective contact sets A-F in the positions shown in FIG. 6. Since the magnetic paths to the selector switches S5-S7 are broken by the presence of the selector card 20, the function control relays RL2-RL4 cannot become actuated at this time.

It will be seen that the presence of the selector switches S2 and S3, one of which is normally closed and the other of which is normally open, function as an antifraud mechanism to prevent operation of the present apparatus simply by inserting a blank sheet of ferrous material into the slot 14, since this action would break the magnetic path maintaining S3 in its actuated state and would prevent any of the function control relays from becoming energized.

A circuit is now established applying control voltage from the line 41 through the contact 44 of RLl-A and along the line 45 to energize the light 46a of the deposit sign 46, and another light 47 corresponding to a predetermined amount of money required to pay for the tank filling prescribed by the particular coded selector card 20. Contact is also now established applying control voltage through the line 40, the line 51, and the contact 52 of RLl-E and the line 53 to a terminal 54 of the rotary stepper switch 55. The stepper switch 55, which may be of the conventional type wherein the switch armature is advanced one step for each voltage pulse applied to a step coil S, is actuated through a coin-controlled switch 56 controlled by deposit of money into the coin slot mechanisms 15. It will be understood that the coin slot mechanism 15, associated apparatus for accepting only proper coins, and the mechanism for operating the coin-controlled switch 56 upon deposit of a particular coin are well-known in the art and the particular details of such coin acceptor mechanisms are not critical to the present invention.

To prevent the stepper switch 55 from being operated before the circuit has been properly conditioned by actuation of one of the function control relays RLl-RL4, the circuit through the coin-controlled switch 56 includes control voltage applied along the line 40 and then passing along a line 57 and the contact 58 of function control relay RLl-F and thence along the line 59 to the stepper coil S.

When the armature of the stepper switch 55 has been moved by appropriate coin-controlled actuation of the switch 56 from the zero position to the terminal 54, to which control voltage was previously applied through closure of the contact 52 of the function control relay RLl-E, a circuit is completed to energize the relay RLS and thus to open the relay contact 60 and extinguish the light 47, thereby notifying the persons using the apparatus that the proper amount of money has been deposited. Control power is also supplied through the line 61 and the contact 62 of the function control relay RLl-D to a time delay circuit 66. The switch contact 66a remains closed until the time delay 66 times out as explained below, and so a control circuit is also completed through the switch contact 66a, a line 67, the contact 68 of the function control relay RLl-C, and the line 69 to a first pressure-actuated switch PS-l. This first pressure-actuated switch PS-l is now in the switching position shown in FIG. 6, and so a circuit is completed through the contact 70 and the diode D1 to energize the relay RL6.

Turning momentarily to a consideration of FIG. 5, it will be seen that the conduit 12 which is connected through the fitting 13 to a scuba tank to receive the predetermined filling of air specified by the selector card 20, extends through the panel 11 into fluid pressure communication with a number of pressureactuated switches and solenoid valves including an air line solenoid valve 71. The conduit is connected as at 72 to receive a source of pressurized gas suitable for filling scuba tanks, in the disclosed embodiment, but air from the source .72 cannot be applied through the conduit 12 to fill a tank until the air line solenoid valve 71 is actuated.

Returning again to FIGS. 6A and 68, it will be seen that the solenoid valve 71 is actuated by closure of the contact 73 established when the relay RL6 is energized. Air now flows from the source 72 through the conduit 12 to commence filling the air tank connected to the fitting 13. A conventional pressure gauge 65 connected to the conduit 12 permits the pressure in the air tank to be monitored.

The tank filling operation continues in progress until the pressure of air in the tank, as monitored by the pressure-actuated switch PS-l disposed in the conduit 12, reaches the predetermined level of 2250 psi (in the example chosen), at which point the switch arm of PS4 is transferred to the contact 74 of that switch. If the person filling an air tank has inadvertently neglected to open the tank valve prior to the filling operation, it will be understood that the pressure-actuated switch PS-l will prematurely switch to the contact 74 as soon as the conduit 12 becomes charged with air to the predetermined pressure of 2250 psi, thus giving a false indication that tank filling has been completed. If this happens, a circuit is completed from the contact 74 through the line 75 and the contact 76a of the time delay 76 to illuminate one of the push hold lights 77. Lighting of the push hold light on the panel 11 informs the operator that he must operate the hold switch 78 to move the switch arm from the contact 78a to the contact 78b, whereupon the HOLD ON light 79 is illuminated and control voltage is removed to close the air line solenoid valve 71 and suspend the tank filling operation. Once the operator has opened the air valve on the tank being filled, he can again operate the hold switch 78 to engage the contact 78a, thereupon recommencing the tank filling operation. The time delay 76 is selected to time out and open the contact 76a after a period of time, such as twenty seconds, which is sufficient to enable the pressure-actuated switch PS-l to operate prematurely if the air tank valve is inadvertently unopened.

When the relay RL6 was previously closed to commence tank filling, control power was also applied through the contact 80 of the function control relay RLl-B, the line 81, and the now-closed contact 82 to a time delay 83. The switch contact 83a closes when the time delay 83 times out, causing the relay RL7 to close. The relay RL7 should remain unactuated until the possibility of a premature fill indication resulting from a closed tank valve is eliminated, and so the time delay 83 is chosen to time out and close the contact 83a approximately 5 seconds, for example, after the time delay 76 times out. Actuation of the relay RL7 establishes a hold circuit through the contact 87 and also closes the relay contacts 88 and 89 to condition the bleed circuit for subsequent actuation.

The time delay 66 is selected to time out and open the switch contact 66a after a period of time selected to be somewhat longer than the time required to com pletely fill a tank of the preselected pressure and volume, so that the pressure-actuated switch PS-l normally will be switched to the contact 74 by attainment of the preselected pressure before the switch contact 66a opens in response to time-out of the time delay 66. The purpose of the time delay 66 will become apparent below. When the control voltage is applied to the contact 74 by the pressure-actuated switch PS1 upon the tank being filled to the predetermined pressure, contact 76a having been previously opened by time-out of the hold circuit time delay 76, the relay RL6 is released to close the solenoid valve 71 and control voltage is applied through the contact 90 and the previously closed contact 88 to illuminate the push bleed light 91. The pressure actuated switch PS-4, which senses the pressure maintained in the conduit 12 following closure of the air line solenoid valve 71 and manual closure of the air tank valve (not shown), maintains the contacts 92 open at this time and so the relay RL8 is not actuated. Illumination of the push bleed light 91 advises the operator to close the air tank valve and actuate the bleed switch 93, whereupon an operating circuit is established through the relay contacts 94 and 89 to close and hold the bleed relay RL9 and to energize the bleed solenoid valve 95. The static pressure trapped in the conduit 12 is thus vented to atmosphere,

at which time the contact 92 of the pressure-actuated switch PS4 closes to apply control power for energizing the relay RL8 through a circuit completed to ground through the switch terminal 43 of the switch S1.

Operation of the relay RL8 opens the switch contact 39, thereby removing control power from the line 40 and the relay RL7 to deenergize the bleed relay RL9 and the bleed solenoid valve 95, and establishes control power through the contact 96 to hold the relay RLS energized. A circuit is also completed through the contact 97 to illuminate the TANK FILLED light 98, reminding the operator to remove his selector card from the slot 14. Card removal opens the control circuit for the relay RL8 established through the contact 43 of the switch S1, and again establishes the operating circuit for the READY light 42. Actuation of the relay RL8 previously applied a control signal through the contact 96 and the line 99 to the reset coil R of the stepper switch 55, causing the stepper switch to be reset to zero. Withdrawal of the selector card from the card slot allows the function control relay RLl to open, and so the apparatus is now in condition to undergo another complete air vending cycle.

Since actual filling of an air tank is not terminated until the pressure-actuated switch PS1 moves to the contact 74, it might be possible for an unscrupulous user of the apparatus to disconnect a partially-filled tank and promptly connect another empty tank to the fitting 13 in an attempt to obtain a free ride tank filling. This is prevented according to the disclosed embodiment of the present invention, however, by opening of the contact 660 upon time-out of the time delay 66, thus opening the control circuit to the line 77 and removing control voltage from the pressure-actuated switch PS-l. The time delay 66 maintains the contact 66a open until the opening of the relay contact 62 allows the time delay to reset. The time-out period of time delay 66 is selected to a period, such as 7.5 minutes, which provides no more than adequate time for filling a tank of 72 cubic feet capacity, in the disclosed embodiment of the invention.

As an alternative to the foregoing described mode of operation, it will now be assumed that a customer operating the present apparatus desires to refill an air tank of 72 cubic feet capacity, the same as before, but having a maximum fill pressure of 1800 psi. This person will be provided with a selector card 20 having apertures at and 23, instead of 25 and 21, thus actuating the function control relay RL2 instead of RLl. It can be seen from FIG. 6 that the actuation of RL2 applies control voltage on the line 45 as described above, to illuminate the lights 46 and 47 and to apply control power to the contact 54 of the stepper switch 55. The operator then is notified to deposit an amount of money as before, since the volume of air being dispensed remains constant at 72 cubic feet, whereupon a control circuit is completed through the line 61 and the contact 102 of the function control relay RL2-D to the time delay 66, and thence through the closed contact 66a, the line 67, and the contact 103 of the function control relay RL2-C to the second pressureactuated switch PS-2; it will be understood that the pressure-actuated switch PS2 is operative to move its switch connect from the depicted position to the contact 104 when the tank fill pressure reaches 1800 psi. The relay RL6 is actuated through PS-Z and the tank fill cycle commences as described previously. A control signal is also applied through the line 105 to a time delay 106 having a contact 106a. The purpose and operation of the time delay 106 is the same as described previously for the time delay 76 and need not be described further.

As a further alternative mode of operation, a person desiring to fill a larger air tank of 144 cubic feet capacity, for example, at a maximum fill pressure of 2250 psi will insert into the card slot 14 a selector card 20 having apertures at 25 and 22 operative to actuate the function control relay RL3. It will be seen that a circuit is completed through the line 107 to illuminate the light 46b of the deposit sign 46 and also the light 108, requiring payment ofa greater sum of money commensurate with the increased volume of air to be vended. A control signal circuit is simultaneously established through the contact 109 of the function control relay RL3-E to the contact 110 of the stepper switch 55. [nsertion of the appropriate sum of money completes a control circuit through the line 61 and the contact 111 of function control relay RL3-D to the time delay 112 having a contact 112a which remains closed until timeout ofa predetermined period. The time delay 1 12 prevents unauthorized free ride filling of a second tank in the same manner as described above for the time delay 66, and it will be appreciated that the time-out period for the time delay 112 is selected to be slightly greater than the time normally required to fill an air tank of the selected larger volume (144 cubic feet in the present example). A time-out period of approximately 15 minutes for the delay 112, for example, is satisfactory for use with the disclosed embodiment.

The control circuit through the contact 112a is completed through the contact 113 of the function control relay RL3-C to the line 69 and the pressure switch PS-l, whereupon the filling operation commences and progresses as described above.

Considering the fourth mode of operation possible with the disclosed embodiment of the present invention, a person desiring to fill a tank of 144 cubic feet capacity to a pressure of 1800 psi will require a selector card 20 having an aperture at 25 and at 24 to actuate the function control relay RL4. A control circuit will be completed from the contact 114 of RL4-E to the contact 110 of the stepper switch 55. The control voltage is then applied through the contact 115 of RL4-D to the contact 112a of the time delay 112, and thence through the contact 116 of RL4-C to the pressureactuated switch PS-2, whereupon the pressure fill operation is initiated.

Although the described embodiment of the present invention affords a selection between two different volumes and two maximum pressures of air tank fillings, it will be apparent to those skilled in the art that a greater or lesser number of pressure and volume selections can be provided according to the present invention, with the appropriate pressure-actuated switches and free ride preventive time delays being provided along with the necessary additional alternative selection capability being provided in the decoding apparatus 27. Similarly, although the use of magnetic switches in conjunction with an apertured ferrous selector card 20 is disclosed herein, those skilled in the art will recognize that different types of apparatus can alternatively be used to provide the proper selection of the desired pressure and the volume of air to be dispensed. It is envisioned that apparatus according to the present invention would be installed at locations such as dive shops or the like and that persons seeking scuba tank refills would be provided with either a temporary or permanent selector card 20 (or comparable device) which he would use to provide authorized access and predetermined pressure-volume fill selection for the apparatus. Such user thus could fill his scuba tanks with little or no attention required by an operator other than himself. It will be appreciated that the use of a selector card 20 which functions only to provide access and fill selection for the apparatus and not credit billing or charge card functions, permits the selector card to be made permanently available to qualified users who must nevertheless make payment before receiving an air tank refill. The pressure-operated switch PS-3 opens to prevent operation of the apparatus in the event of an inadequate air pressure supplied at 72.

Although the use of relays and other electromechanical elements are shown in the disclosed embodiment, it will be appreciated that devices such as solid-state switches and the like can be substituted in other embodiments of the present invention. Moreover, although the disclosed embodiment of the invention has been discussed herein with reference to the particular application of scuba tank refilling, it will be understood that this use is by way of example only and that apparatus according to the present invention can be used to dispense various types of gases into pressure tanks or vessels intended for uses other than divers air supply.

Furthermore, the foregoing relates only to a particular embodiment of the present invention, and numerous alterations and modifications may be made therein without departing from the spirit and the scope of the present invention as set forth in the following claims.

What is claimed is:

l. Compressed gas dispensing apparatus, comprising conduit means connectable between a source of compressed gas and a gas receiving receptacle;

valve means operatively disposed in said conduit means to selectively control the flow of gas therethrough;

first means operatively responsive to a first variable quantity of the gas dispensed to the gas receiving receptacle to provide a first signal condition when a certain selected amount of said first quantity occurs;

second means operatively responsive to a second variable quantity to provide a second signal condition when a certain selected state of said second quantity occurs;

control circuit means selectively operative to open said valve means to permit gas flow therethrough, said control means being operative in response to said first signal condition from said first means and in response to said second signal from said second means to close said valve means in response to either of said first and second signals; and

timing means operative to provide an alarm signal condition in response to the occurrence of said first signal condition within a certain period of time after said valve means is opened.

2. Apparatus as in claim 1, wherein said first means is responsive to the pressure of gas in the receptacle.

3. Apparatus as in claim 2, wherein:

said second means is operative in proportion to the volume of gas supplied to the receptacle.

4. Apparatus as in claim 3, wherein:

said second means comprises timing means operative to produce said second signal after said valve means has been open to supply to the receptacle for a predetermined period of time.

5. Apparatus for dispensing compressed gas to a receptacle, comprising:

enabling means operative to select one of a plurality of circuits corresponding to a plurality of different certain pressures and volumes of gas to be dispensed;

payment acceptor means operative in response to the circuit selected by said enabling means to establish a circuit condition indicating required payment of a certain sum of money,

said payment acceptor means operative in response to payment of said certain sum to establish a control circuit;

valve means disposed to control the flow of gas from a source of compressed gas to a gas receiving receptacle,

said valve means operative in response to establishment of said control circuit to open and permit the dispensing flow of gas to the receptacle;

first means responsive to the pressure of the gas in the receptacle and also responsive to the circuit selected by said payment acceptor means to provide a first signal condition when the pressure exceeds a certain predetermined amount corresponding to said selected circuit;

second means responsive to said selected circuit and operative to provide a second signal condition related to the delivery of a certain predetermined volume of gas as selected by said selected circuit; and

said valve terminating said flow of gas to the receptacle in response to either of said first signal condition or said second signal condition.

6. Apparatus as in claim 5, further comprising:

pressure conduit means extending from said valve means for selective connection to the gas receiving receptacle;

a bleed valve in communication with said pressure conduit means and selectively operable to vent to atmospheric pressure the gas pressure trapped in said conduit means;

bleed valve control circuit connected to said bleed valve and selectively operable in response to the occurrence to either of said first and second signal conditions to open said bleed valve; and

bleed pressure responsive means responsive to the gas pressure in said pressure conduit means and operative to close said bleed valve when the gas pressure in said pressure conduit means falls to a predetermined level.

7. Apparatus as in claim 5, further comprising:

pressure conduit means extending from said valve means for selective connecting to a gas receiving receptacle having a valve which is selectively operable to admit the dispensed gas to the receptacle;

timing means responsive to said control circuit operative concurrent with the initiation of the dispensing flow of gas to define a period of time which is a predetermined amount greater than the amount of time for the gas pressure in said pressure conduit to exceed said predetermined certain pressure when the valve of the receptacle remains closed to prevent gas from entering the receptacle; and

signal means operative to provide a signal in response to operation of said first means during said period of time defined by said timing means.

8. Apparatus as in claim 5, wherein:

said second means comprises dispensing timing means responsive to said selected circuit and operative in response to said control circuit to define a certain period of time which is sufficient to dispense not substantially more than said certain predetermined volume of gas to the receptacle; and

said dispensing timing means operative to provide said second circuit condition upon reaching said certain period of time.

9. Apparatus as in claim 8, further comprising:

plural ones of said first means each operative to provide said first signal condition responsive to a selected predetermined pressure of the gas in the receptacle;

plural ones of said dispensing timing means each operative to define a certain time period which is sufficient to dispense not substantially more than a selected predetermined volume of gas;

each of said plural circuits of said enabling means connected to one of said plural first means and to one of said plural dispensing timing means;

said enabling means is operative to sense information on a coded member corresponding to a selected one of said plurality of pressures and also corresponding to a selected one of said plurality of volumes; and

said enabling means is operative in response to said sensed information to select the appropriate one of said plural circuits which is connected to the first means and to the dispensing timing means corresponding to said sensed pressure and volume information.

10. Apparatus as in claim 9, wherein:

said enabling means comprises a plurality of swiches which are actuated by the presence of a magnetic field, at least some of said plural switches being operatively associated with corresponding ones of said plurality of circuits corresponding to predetermined pressures and volumes of gas to be dispensed;

means disposed to maintain a magnetic field in actuating relation with each of said plural switches;

said coded member comprises magnetic shield means which is selectively positionable between said plural switches and said magnetic field means to prevent the magnetic field from actuating said plural switches; and the said mangetic shield means having at least one interruption therein to allow the magnetic field to maintain actuating relation with at least one of said plural switches. 

1. Compressed gas dispensing apparatus, comprising conduit means connectable between a source of compressed gas and a gas receiving receptacle; valve means operatively disposed in said conduit means to selectively control the flow of gas therethrough; first means operatively responsive to a first variable quantity of the gas dispensed to the gas receiving receptacle to provide a first signal condition when a certain selected amount of said first quantity occurs; second means operatively responsive to a second variable quantity to provide a second signal condition when a certain selected state of said second quantity occurs; control circuit means selectively operative to open said valve means to permit gas flow therethrough, said control means being operative in response to said first signal condition from said first means and in response to said second signal from said second means tO close said valve means in response to either of said first and second signals; and timing means operative to provide an alarm signal condition in response to the occurrence of said first signal condition within a certain period of time after said valve means is opened.
 2. Apparatus as in claim 1, wherein said first means is responsive to the pressure of gas in the receptacle.
 3. Apparatus as in claim 2, wherein: said second means is operative in proportion to the volume of gas supplied to the receptacle.
 4. Apparatus as in claim 3, wherein: said second means comprises timing means operative to produce said second signal after said valve means has been open to supply to the receptacle for a predetermined period of time.
 5. Apparatus for dispensing compressed gas to a receptacle, comprising: enabling means operative to select one of a plurality of circuits corresponding to a plurality of different certain pressures and volumes of gas to be dispensed; payment acceptor means operative in response to the circuit selected by said enabling means to establish a circuit condition indicating required payment of a certain sum of money, said payment acceptor means operative in response to payment of said certain sum to establish a control circuit; valve means disposed to control the flow of gas from a source of compressed gas to a gas receiving receptacle, said valve means operative in response to establishment of said control circuit to open and permit the dispensing flow of gas to the receptacle; first means responsive to the pressure of the gas in the receptacle and also responsive to the circuit selected by said payment acceptor means to provide a first signal condition when the pressure exceeds a certain predetermined amount corresponding to said selected circuit; second means responsive to said selected circuit and operative to provide a second signal condition related to the delivery of a certain predetermined volume of gas as selected by said selected circuit; and said valve terminating said flow of gas to the receptacle in response to either of said first signal condition or said second signal condition.
 6. Apparatus as in claim 5, further comprising: pressure conduit means extending from said valve means for selective connection to the gas receiving receptacle; a bleed valve in communication with said pressure conduit means and selectively operable to vent to atmospheric pressure the gas pressure trapped in said conduit means; bleed valve control circuit connected to said bleed valve and selectively operable in response to the occurrence to either of said first and second signal conditions to open said bleed valve; and bleed pressure responsive means responsive to the gas pressure in said pressure conduit means and operative to close said bleed valve when the gas pressure in said pressure conduit means falls to a predetermined level.
 7. Apparatus as in claim 5, further comprising: pressure conduit means extending from said valve means for selective connecting to a gas receiving receptacle having a valve which is selectively operable to admit the dispensed gas to the receptacle; timing means responsive to said control circuit operative concurrent with the initiation of the dispensing flow of gas to define a period of time which is a predetermined amount greater than the amount of time for the gas pressure in said pressure conduit to exceed said predetermined certain pressure when the valve of the receptacle remains closed to prevent gas from entering the receptacle; and signal means operative to provide a signal in response to operation of said first means during said period of time defined by said timing means.
 8. Apparatus as in claim 5, wherein: said second means comprises dispensing timing means responsive to said selected circuit and operative in response to said control circuit to define a certain period of time which is sufficient to dispense not Substantially more than said certain predetermined volume of gas to the receptacle; and said dispensing timing means operative to provide said second circuit condition upon reaching said certain period of time.
 9. Apparatus as in claim 8, further comprising: plural ones of said first means each operative to provide said first signal condition responsive to a selected predetermined pressure of the gas in the receptacle; plural ones of said dispensing timing means each operative to define a certain time period which is sufficient to dispense not substantially more than a selected predetermined volume of gas; each of said plural circuits of said enabling means connected to one of said plural first means and to one of said plural dispensing timing means; said enabling means is operative to sense information on a coded member corresponding to a selected one of said plurality of pressures and also corresponding to a selected one of said plurality of volumes; and said enabling means is operative in response to said sensed information to select the appropriate one of said plural circuits which is connected to the first means and to the dispensing timing means corresponding to said sensed pressure and volume information.
 10. Apparatus as in claim 9, wherein: said enabling means comprises a plurality of swiches which are actuated by the presence of a magnetic field, at least some of said plural switches being operatively associated with corresponding ones of said plurality of circuits corresponding to predetermined pressures and volumes of gas to be dispensed; means disposed to maintain a magnetic field in actuating relation with each of said plural switches; said coded member comprises magnetic shield means which is selectively positionable between said plural switches and said magnetic field means to prevent the magnetic field from actuating said plural switches; and the said mangetic shield means having at least one interruption therein to allow the magnetic field to maintain actuating relation with at least one of said plural switches. 